There's plenty they could do to improve on K2, short of adding color:
- make it faster
- internationalize the hardware/software (for non-English languages). This would probably mean scrapping the so-called keyboard and replacing it with a touchscreen (either a second screen like Nook or a single touch sensitive screen for reading and typing). Kindle is really the only dedicated reader device that is so strongly tied to the English language, and Amazon needs to address this if they want to compete globally.
- improve screen contrast
- lower the price to $300